qpdf: Link with libatomic on rv32

Fixes
libqpdf/build/.libs/libqpdf.so: undefined reference to `__atomic_fetch_add_8'

Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-oe/recipes-printing/qpdf/qpdf_10.0.1.bb

@@ -21,6 +21,7 @@ EXTRA_OECONF = "--without-random \
 EXTRA_OEMAKE_class-target = "LIBTOOL=${HOST_SYS}-libtool"
 
 LDFLAGS_append_mipsarch = " -latomic"
+LDFLAGS_append_riscv32 = " -latomic"
 
 S="${WORKDIR}/${BPN}-${PV}"